Magnetic stick type relay having saturable core member



Dec. 8, 1964 M. A. scHEG 3,160,795

MAGNETIC STICK TYPE RELAY HAVING SATRABLE CORE MEMBER Filed March 30, 1960 HIS ATTORNEY United States Patent C)` Milf/95 MAGNETC Siltll TYPE HAVEN@ SATURAEILE @SRE MEMBER Marciana A. Scheg, Rochester, NSY., assigner to General Corporation Filed Mar. 3h, I@ y, Ser. No. 1%,760 14 Claims., (Qi. S17-171) This invention generally relates to electrical relays and more particularly pertains to the magnetic stick type relay adapted for railway use.

ln the various railway applications of the magnetic sticlt type relay; ie., a relay which assumes either of its two possible operating positions in accordance with the polarity of the energization to the electromagnetic structure ot the relay and which remains iny its last operated position until application of the opposite polarity of energization, it is necessary to place the relays side by vspecifically proposed to construct a relay having a permanent magnet and an energizing winding each of which acts upon the relay in such a manner that its armature is properly operated by energizations of its winding and is held in an operated position by the permanent magnet. But such permanent magnetic force is so located and shunted in such a way as to reduce its ei'iects on neighboring adjacent relays. It is also proposed that this shunting of the permanentv magnetic force be accomplished by means which assists the relay armature to be operated eiiciently to eitherfposition in which such armature is held even though its winding is deenergized. Also, the energizing winding is so located as to minimize its aiiect on adjacent relays.

A general object of this invention is to provide a magnetic stick type relay which is small and compact and which is therefore suitable for mounting on racks.

Other objects, purposes and characteristic features of the present invention will be in part obvious from the accompanying drawings, and in part pointed out as the description of the invention progresses.

In describing the invention in detail, reference will be made to the accompanying drawings, in which like reference characters designate corresponding parts throughout the several Views, and in which:

FIG. 1 is a top view of two identical relays of this invention mounted side by side on a single base;

FIG. 2 is a side elevation of the same relays as shown in FlG. l with parts shown in section to illustrate the construction of the base and electromagnct structures of the two relays; y

FIG. 3 is a front elevation of the same relays as shown in FIGS. 1 and 2 with certain parts broken away to illustrate the position of the permanent magnet structure of the relays; and

FIG. 4 is an isometric View of the clamping device used to retain the permanent magnet structures of these relays in a fixed position.

Reerringl now to the accompanying drawings, two identical relays embodying this invention areshown mounted on the same base. rThese two relays operate in ICC response to the applied electrical energy and their operating actions are made electrically independent in accordance with the principles of the present invention. Assuming that each of the illustrated relays is electrically independent from the other, the description of the construction and operation of one relay will be set forth in detail, and it will be assumed the other relay is exactly identical.

Referring now to FIG. 2 of` the accompanying drawings, the relay of this invention includes a nonrnagnetic base 1) attached to the short leg of an L-shaped magnetic yoke 11 by rivet 12 and also carrying a magnetizable elongated core 13 which is firmly held to base 10 and the magnetic yoke 11 by bolt 14 which is tightly threaded into one end of the magnetizable core 13. A spool 15, having enlarged end pieces 15A and 15B, and a cap 16 are clamped firmly upon the magnetizable core 13 and against a leaf spring 17 by retaining pin 18 which is positioned through the magnetizable core 13 and held firmly in place in a transverse slot in the enlarged end piece 15A of spool 15. n

Spool 15 also carries an energizable winding 19, concentrated towards the base l0 and having connected to it contact tips 19A. which extend to the right in FIG. 2 through base 10 for connection with suitable plug contacts (not shown) in order to supply electric current to the energizable winding 19, and a spacer 20 filling up the remaining space towards its extending left-hand end in PEG. 2. Cap 16 includes a sleeve portion which also extends to the right in FIG. 2 and which encircles contact tips 19A for the purpose of electrically insulating the contact tips lA from the nonmagnetic metallic base structure.

The long leg of the l.-shaped magnetic yoke 11 isconstructed with a slot 21, a little forward of its center portion, and has riveted to it a nonmagnetic back stop plate 22 which has a relatively thin portion extending just past the free left-hand end of this leg of the L-shaped magnetic yoke l1. A magnetic L-shaped armature 23 is pivotally mounted on rthe tree end of the long leg of the L-shaped ymagnetic yoke 11 and is formed with a small slot which loosely engages the extending end of the relatively thin portion of the nonmagnetic back stop plate 22 for preventing downward shifting of armature 23. The long leg of armature 23 carries a residual screw 24 and an associatedl nut 25 in such a manner that the residual screw 24- hangs in front of the pole face end of the magnetizable core i3. Residual screw 24 is provided to allow for adjusting the release current of the relay and is held in its adjusted position by nut 25.

The upper short le(Y of the magnetic L-shaped armature 2.3 carries an extension member 26, made of suitable insulating material, which extends to the rear of the magnetic L-shaped armature 23 and rests firmly upon back Astop plate 22 when the armature 23 is in its released position thus determining this release position 'of armature`-=23- An adjustable magnetic screw 27 y which is threaded through armature 23 so that its extending portion canbe freely moved within an oversized hole in the relatively thick portion of the nonmagnetic back stop plate 22 in such a manner that a small air gap A alwaysexists between `the lower end of screw 27 and 4the ytop edge of the long legof the L-shaped magnetic yokejll. y'Screw 1?;7 is tightly held in its 'adjusted position by nut 2S.

rbatir stop plate 22 by screw 30 and nut 31.` Retaining Referring to` FIG. 2,y the above mentioned oversized hole is positioned slightly in back of, or'in other amarga "Ivi d plate 29 also serves the purpose of preventing the magnetic L-shaped armature 23 from moving either away from the free end of the long leg of magnetic yoke 11 or in a side to side direction, thus retaining the armature 23 always directly in front of the free end of the long leg of the L-shaped magnetic yoke 11.

Two contact blocks 32, of suitable insulating material, are secured to the upper portion of base 1t), each contact block .32 being secured by a screw 33 which is threaded into contact block 32 and by a spring loaded screw 344 which is tightly held in an adjusted position by nut 35. Each contact block 32 also carries a contact row consisting of front contact member 36, movable contact member 37 and back contact member 33. Of these, front and back contact members 36 and 3S are formed of bifurcated metal springs and are held rmly in stationary positions by rigid stops 39 which are also carried by contact block 32. ln addition, each Contact block 32 also carries a resilient idler finger dit which extend to the left in FIG. 2 and has its extreme free end resting firmly on the extension member 26 for the purpose of continually biasing the magnetic armature 23 towards its released position.

Two contact pushers i1 (one for each contact row), of suitable insulation, are mounted in slots in movable contact members 37 and have their lower ends in slots in idler fingers et) which rest on the edge of extension member 26 for providing vertical displacement to the movable contact members 3'7 to engage front contact members 36 when the magnetic armature 23 is attracted towards the pole face end of core 13. This retainment of contact pushers 41 in slots in idler fingers 40 insures that the movement of contact pushers i1 will be always in the desired Vertical direction.

Contact members 36, 37 and 3S furthermore extend continuously to the right in FIG. 2 past contact block 32 and terminate in contact tips d2 for the purpose of engaging plug contacts of a suitable plug board (not shown).

It is evident Ifrom the above and `from the included drawings that the spring loaded screws 34 are provided to adjust the movable contact members 37 with respect to their respective iixed iront and back contact members 36 and 38 so as to be in a central position. This adjustment of movable contact members 37 causes a normal contact lload on the armature 23 through the medium of the contact pushers d1 and idler fingers 40 and furthermore assures proper engagement of movable contact members 37 with back contact members 38, when the armature 23 is released away from the pole vface end of core 13. In addition to such contact load, the resilient idler fingers d@ themselves also provide an armature load `which in the assembly of the relay is adjusted to provide the desired total load on the armature 23, so that the desired operating values for the relay may be readily obtained.

The long leg ofthe L-shaped magnetic yoke 11 furthermore carries a permanent magnet .43 which is held firmly against the underside of and centered at the slot 21 in this long leg of yoke 11 by a non-magnetic clamp 44 and a non-magnetic screw 45 which extends upwardly and is tightly threaded into the relatively thick portion of non- -magnetic back stop plate 22. The positioning of permanent magnet 43 in clamp iftis illustrated in FIG. 4 ot the accompanying drawings and by referring to FIG. 2 it is seen that the permanent magnet 43 is assumed positioned with its north pole N towards the free end of the long leg of the L-shaped magnetic yoke 11 and its south pole S towards'the base 19. In addition, it should be pointed out that permanent magnet i3 has been manufactured so that its magnetic poles N and S appear in the vicinity of the top edge of permanent magnet d3 which contacts the long leg of the L-shaped magnetic yoke 11 in FIG. 2, thus reducing the leakage of magnetic flux across the air gap between the long leg of armature 23 and the left-hand edge of permanent magnet 43. Furthermore, the enlarged end piece .15A of spool i 15 is constructed so that the top edge of end piece 15A rests against the underside of permanent magnet 43 to firmly tix the position of permanent magnet 43. In addition, this construction helps to prevent any turning of spool 15 upon magnetizable core 13.

Referring to FIG. 2 of the accompanying drawings, if it is now assumed that armature 23 is in its released position (as illustrated) and winding 19 has been deenergized, it is apparent that some magnetic tlux from permanent magnet d3 flows out of the north pole l of this permanent magnet, across the slotted portion of the long leg of the magnetic yoke 11, and to south pole S7 of permanent magnet 43. The depth of slot 21 is so chosen that this tlow of permanent magnet iiux magnetically saturates the narrow portion of magnetic yoke 11 at the top of slot 21 in FIG. 2 and it is considered that this saturation, in effect, causes the slotted portion of magnetic yoke 11 to be a relatively high reluctance for any additional flux which may attempt to traverse this slotted portion of magnetic yoke 11 from left to right in FIG. 2.

In addition to the above mentioned flow of magnetic flux, a certain portion of the permanent magnet luX flows from the north pole end N of the permanent magnet to the free end of the long leg of the L-shaped magnetic yoke 11, through the long leg of the magnetic armature 23 and across the air gap B between armature Z3 and the pole face end of the magnetizable core 13, through core 13 and returns to the south pole end S of the permanent magnet 43 by way of the back short leg portion of the L-shaped magnetic yoke 11. Furthermore, a still further portion of the permanent magnet iiux flows from the north pole end N of the permanent magnet through the short leg of the L-shaped magnetic armature 23, down the magnetizable screw 27 and across the small air gap A between the lower end of screw 27 and the magnetic yoke 11, and to the south pole end S of permanent magnet 43.

it is obvious that this last mentioned ow of permanent magnet linx causes a magnetic `force to be produced at gap A which pulls the short leg of the magnetic L-shaped armature 23 towards the top edge of the long leg of the magnetic L-shaped yoke 11. Although the armature 23 is prevented from moving, since in its released position the extension member 26 is resting firmly upon the non-magnetic back stop plate 22, this produced magnetic force nevertheless assures that once the armature 23 is in its released position it will remain there and be substantially unaffected by any detrimental magnetic inter-ference from neighboring relays or extraneous vibrations or the like.

Although the iiow of permanent magnet flux across air gap B between the -lower end of armature 23 and the pole face end of the magnetizable core 13 also produces a slight pulling vforce at this air gap, the armature 23 is prevented from moving towards the pole face end of core 13 by the combined eiiects of the magnetic force at gap A, the contact load, and the resilient idler fingers 40.

1f the winding 19 is energized with current of a polarity such as to produce magnetic tlux in the core 13 with a south pole at its left-hand end and a north pole at its right-hand end, the electromagnetic flux will pass through the magnetic yoke 11 in a way to oppose the how of flux through the air gap A from the permanent magnet and to increase the flow of iiux 'from the north pole end N from the permanent magnet through the left-hand end of the core-13 and the air gap B. The increase in iiux in the air gap B and the decrease in nur; in the air gap A causes the armature 23 to be attracted to operate the contacts against their spring pressures.

When the air gap B has been reduced'to its minimum value where the armature 23 is in a fully operated position with the residual pin 24 contacting the face of the core 13, the energization of the Winding 19 may be removed and the armature 23 will be held in such operated position by the permanent magnet flux passing from the north pole e'nd N of the permanent magnet 43, through the armature 23, core 13, yoke 11 to the south pole end S of the permanent magnet 43. Since the air gap A is now considerably increased in length, there is very little permanent magnet flux following through such air gap. Thus, the net result is that the armature 23 is magnetically held in its operated position.

If the Winding 19 is now energized with the opposite polarity of current, such that the left-hand end of core 13 is made a north pole, this electromagnetic flux opposes the permanent magnetic flux flowing across the air gap B thus reducing the pull of the armature 23 with respect to that air gap. The electromagnetic ux flowing from the core 13 to the armature 23 cannot effectively increase the magnetic flux passing through the slotted portion of the magnetic yoke 11 since it is magnetically saturated by the flux from the permanent magnet 43. However, the llux from the permanent magnet is diverted from its north pole into the short leg of the armature 23 and tends to pass through the air gap A. In addition, the electromagnetic flux may also add to this so as to create a substantial pull in the air gap A. In any event, the reduction of the pull in air gap B on the armature 23, the increase in pull in the air gap A, the contact pressure, and thespring tension of the idler springs, all add together to cause the armature 23 to assume a release position in which its right-hand end rests against the back stop plate 22. With the armature in this position, and the magnetic screw 27 properly adjusted to produce the appropriate air gap A, the flux which flows through this air gap A from the permanent magnet 43 (since the slotted portion of the yoke 11 is saturated) is sufficient to magnetically hold the armature in its released position in spite of external conditions of vibrations or magnetic influences.

As mentioned above, the permanent magnet 43 is preferably of such a size as to just saturate the slotted portion of the yoke 11, on the other hand the permanent magnet 43 may be made considerably stronger and thus cause magnetic flux in the slotted portion of the yoke 11 to have a density considerably in excess of the density required for saturation.

Assuming that the slotted portion of the yoke 11 has a density produced by the permanent magnet approximating the saturation value, and the relay winding is energized for armature operation when the relay armature 23 is in a released position as shown, one theory is that the electromagnetic flux may be sufficiently strong in such a case to overcome the magnetic flux passing through the slotted portion of the yoke 11 and thus provide an effective path for some of the electromagnetic flux that passes through the air gap B to be added to the permanent magnet ilux which is diverted away from the air gap A and thus cause the operation of the armature.

In the case where the premanent magnet 43 is assumed to be sufficiently strong as to produce a flux density in the slotted portion of yoke 11 considerably beyond the flux density required for saturation, then the theory of operation may be considered slightly different. In this instance, the electromagnetic flux may be said to oppose the permanent magnetic flux and divert it to the air gap B in such a way as to cause operation of the armature 23 by permanent magnet flux without substantial additional llux in such air gap B being supplied by the electromagnet. In this instance, the flux flowing in the air gap A may preferably be just reduced to zero so that no added load is placed on the relay for the operation of the contacts.

It is of course assumed that the appropriate size of air gap B is selected for the operation of the contacts, and that the air gap A is adjusted to obtain the desired holding effect when the armature is in a released position. Let us assume that the winding 19 is energized with that polarity of current to cause the release of the armature. The resultant electromagnetic flux produces a north pole at the left-hand end of the core 13 which is in opposition to the permanent magnet flux, and which cannot increase the flux in the slotted portion of the yoke 11 because of its saturated condition; but the increased electromagnetic flux does` pass through the short leg of the armature 23 and the air gap A If such release energization of the winding 19 is increased beyond the normal value, such increase merely causes :added electromagnetic llux to appear in the air gap A and thus hold the armature 23 against erroneous and undesired operation. This path for the electromagnetic flux through the short leg of the armature 23-and the .air gap A also protects the permanent magnet 43 against demagnetization effects during such excessive energizations.

It will be noted that the permanent magnet is located very closely adjacent to the holding air gap A and to the operating air gap B so that its effect in holding the relay armature 23 in its last operated position can be accomplished without having the premanent magnet unduly strong. This minimizes the effect of the permanent magnet for one relay upon the holding effect of the permanent magnet of the adjacent relay. Since the permanent magnet 43 is so magnetized as to have its poles along its upper edge, the shunting yoke 11 acts effectively to shunt stray flux .and keep it within the magnetic structure of its own relay. Any stray flux from the ends of the magnet can readily seek paths through the surrounding core and armature, and in so doing merely increases the holding effect of the permanent magnet on the armature for the position in which it then rests. This is highly advantageous in minimizing the interference effect between adjacent relays.

By positioning the operating winding 19 towards the base end of the core 13 (i.e. to the right yin FIG. 2) instead of over the entire length of core 13, it has been found that the energization. of such winding produces less magnetic interference effects on adjacent relays on either side, such as for example, between the two relays shown in FIG. 3. This is believed to be true 4because when the winding 19 is energized, the major portion of the magnetic leakage around such winding may have two effects on an adjacent relay, i.e. (l) such leakage flux may cut the yoke 11 and the core 13 of an adjacent relay, but the two fluxes thus produced will cancel each other; and (2) such stray flux may act upon the holding and operating air gaps A and Bf Because the winding 19 is located toward the base of core 13, it is a relatively great distance from the susceptible operating air gap B of the adjacent relay; and since the force producing capabilities of the magnetic leakage flux varies inversely with the distance from the source of magnetic leakage flux, it is apparent that such leakage flux could not substantially effect the operating air gap B of an adjacent relay either during its operation or during the holding effect of the permanent magnet on the armature in its operated position. Due to the fact that the air gap A on any relay is ofthe holding type and is constructed to provide only a relatively small amount of operational torque for releasing purposes, any stray flux from the energizing winding of an adjacent electromagnet would have little or no effect upon it while the relay is being held by its permanent magnet in an operated position, and when in a released position such stray magnetic flux whether additive or subtractive to the holding effect is substantially immaterial since the contact load is always present.

From the above, it should be apparent that the magnetic interference effects between adjacent relays has been greatly minimized.

As mentioned previously Vthe'depth of slot 21 in the long leg of the magnetic yoke 11 is properly selected in accordance with the design of the relay involving the strength of the permanent magnet, the degree of energization required by an energizing winding for operation and the size of the various parts. However, it ycan be generally stated that the depth of the slot has a direct bearing on the magnetic leakage considerations. particular design of relay, it has been foundexperimentally For one i sacarse that such slot has an effect to reduce the interference between relays such that when there is no slot, an adjacent relay upon energization of its operating winding, may etfect the release of the armature; but, when a slot is provided of an appropriate depth, this effect has been reduced very substantially and to an extent that it may be disregarded. From this it can be seen that the presence of a slot in the yoke lit not only is involved in the relationship of the permanent magnet to the relay, but is also involved in the reducing of the interference between adjacent relays upon the energization of operating windings.

One theory is that if the slot is too large, or in the extreme the yoke li might be cut completely through, there would be a relatively large build up of undesirable magnetic leakage flux from the permanent magnet so that leakage tlux from an adjacent electromagnet might cause a diversion of the permanent magnet ux in an adjacent relay; whereas, if the depth of the slot were too small the permanent magnet might be unduly shunted and supply insutlicient permanent magnet ilux to retain an armature in its last operated position. However, it is to be understood that the exact theory of the operation is immaterial to the actual practice of the invention, since the relation of the parts as shown and described above is sufcient to construct relays of the magnet stick type which have a minimum of interfering iniluences upon each other which can be determined by the construction of the slot in the shunting back yoke to a point where the connection between the opposite sides of the slot is saturated by permanent magnet iiux and the operating values ot the relay are in conformance with the desired efciency.

From the accompanying drawings and the foregoing description it is therefore apparent that a magnetic stick type relay has been provided which has very little magnetic effect on its neighboring relays and in which the armature is magnetically held in its last operated position after deenerg-ization of the relay electromagnet in such a manner that spurious operation of the relay, as might result from magnetic interference from an adjacent relay, is essentially eliminated, thus rendering this form of magnetic stick type relay particularly suitable for multiple operation with other relays, wherein it is necessary to mount the relays side by side on relay racks.

Having described a magnetic stick type relay, as one specilic embodiment of the present invention, it is desired to be understood that this form is selected to facilitate in the disclosure of the invention rather than to limit the number of forms which it may assume and, it is to be further understood that obvious modifications, adaptations o and alterations may be applied to the speciiic form shown to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention.

What I claim is:

1. In an electromagnetic relay, a core structure and an armature pivotally mounted to have its opposite ends cooperate with said core structure, said core structure providing distinct magnetic iiuX paths for each of the two positions of said armature, a Winding on said core structure energizable selectively to produce iiux of each of two polarities in said core structure, and a permanent magnet mounted in shunting relationship with a portion of said core structure and causing the saturation of that portion of said core structure to cause said flux from said 6 end ot said permanent magnet and said saturable member for completing the operating magnetic circuit associated with each position of said armature, and a winding on said core structure for producing magnetic linx in the operating magnetic circuits completed by said magnetic core structure, said permanent magnet and said saturable member serving to selectively route the magnetic ilux produced by said winding to the magnetic circuits completed by said core structure for operating said armature to its two positions in accordance with the polarity of energization to said winding.

3. In an electromagnetic relay, a U-shaped core structure having an energizing winding on one leg thereof and a permanent magnet mounted in shutting relationship with and magnetically saturating a portion of the other leg thereof, a two position L-shaped armature pivoted at its central portion adjacent that leg of the core structure having the permanent magnet mounted thereon to have one leg of the L-shaped armature adjacent the ends of said core structure and the other leg of the L-shaped armature adjacent the leg of the core structure having the permanent magnet thereon, and spring 'contacts operably connected to said armature and normally biasing it to have its leg [adjacent said core structure and permanent magnet biased toward said permanent magnet, whereby said permanent magnet is effective to hold said armature in either of its two positions, and whereby said armature is operated selectively to its two positions dependent upon the polarity of the energizat-ion of said winding.

4. An electromagnetic relay in accordance with the preceding claim 3 in which said core structurel has a reduced cross section adjacent the midportion of Said permanent magnet to permit said permanent magnet to normally saturate said reduced portion of said core structure with its magnetic uX.

Y 5. An electromagnetic relay in accordance with claim 3 in which that leg of the core structure upon which said permanent magnet is mounted is reduced in cross section (t the midportion of said permanent magnet, and in which the magnetic path formed by that leg of the L- shaped armature adjacent the permanent magnet is adjustable.

6. An electromagnetic relay constructed in accordance with claim 3 in which said winding is relatively short and is mounted to the rear of that leg of said core structure supporting it.

7, In an electromagnetic relay, a core structure and a cooperating two position pivoted armature, said core structure providing distinct magnetic flux paths for each of the two positions of said armature, a winding on said core structure energizable selectively to produce flux of each of two polarities in said core structure, and a permanent magnet mounted in shunting relationship with :a portion of said core structure and causing the saturation of that portion of said core structure to cause said ilux from said winding to pass selectively through said distinct flux paths to said armature dependen-t upon the polarity of such ux, said saturated portion of said core structure having a reduction in cross sectional area, between the magnetic poles of said permanent magnet, to permit such permanent magnet saturation, but having suicient cross section to prevent the build up ot a magnetic potential difference across the magnetic poles of said permanent magnet external to the operating magnetic circuits of the relay.

8. In an electromagnetic relay, a core structure and a cooperating two position pivoted armature, said core structure providing distinct magnetic flux paths for each of the two positions of said armature, a winding on said core structure energizable selectively to produce ilux of each of two polarities in said core structure, and la permanent magnet mounted in shunting relationship with a portion of said core structure and causing the saturation of that portion of said core structure to cause said lluX from said winding to pass selectively through said distinct tlux paths to said armature dependent upon the adsense polarity of such flux, said permanent magnet having its magnetic poles closely yadjacent that portion of said core structure upon which said permanent magnet lis mounted.

9. In an electromagnetic relay, a core structure and a two position armature pivotally mounted to have its opposite ends movable towards and away from said core structure, said Core structure providing distinct magnetic linx paths to said armature for each position of said armature, a winding on said vcore structure energizable selectively to produce magnetic flux of each of two polarities in said core structure, and a permanent magnet mounted in shnnting relationship with a portion of said core structure and causing the magnetic saturation of said portion whereby the magnetic ilux produced by said winding is selectively effective through said distinct magnetic flux paths to operate said armature to either of its positions in accordance with the polarity of energization of said Winding, said permanent magnet also supplying magnetic flux to said distinct magnetic llux paths following each operation of said armature for retaining said armature in its last operated position subsequent to the deenergization of said winding.

10. In an electromagnetic relay, a core structure and an armature pivotally mounted to have its ends movable in opposite directions relative to said core structure between irst and second operating terminal positions of said armature, a Winding on said core structure energizable selectively in accordance with the desired operating terminal position of said armature to produce magnetic ilux in said core structure, and a permanent magnet mounted in shunting relationship with and magnetically saturating a portion of said core structure for selectively routing the magnetic flux produced by said winding over selected distinct magnetic flux paths in said core structure effective selectively to operate said armature to the desired operating terminal position of said armature dependent upon the selective energization of said Winding, said permanent magnet retaining said armature in its last operl0 ated terminal position subsequent to the deenergization of said winding.

11. An electromganetic relay in `accordance with claim 3 in which said permanent magnet is mounted on said U-shaped core structure relatively close to the ends of said core structure.

12. An electromagnetic relay in accordance with claim 3 in which said permanent magnet is mounted on said U-shaped core structure so yas to lie within the space between the legs of said core structure.

13. In an electromagnetic relay, a U-shaped core structure and a ycooperating two position pivoted armature, a winding mounted on one leg of said core structure and energizable to produce magnetic uX of each of two polarities in said core structure, and a permanent magnet mounted in shunting relationship with and magnetically saturating a portion of the other leg of said U-shaped core structure, whereby said armature is operated selectively to its two positions dependent upon the polarity of energization of said Winding and whereby said permanent magnet is effective to hold said armature in either of its operated positions when said winding is deenergized, said permanent magnet funthermore being mounted so as to lie within the space between the legs of said U-shaped core structure.

14. The electromagnetic relay according to claim 13 wherein the legs of said U-shaped core structure are relatively close together.

References Cited in the le of this patent UNITED STATES PATENTS 1,138,677 Lum e May 11, 1915 2,375,017 Marrison May 1, 1945 2,535,977 Willing et al Dec. 26, 1950 2,710,365 MacDougall et al. June 7, 1955 2,935,656 Baker May 3, 1960 3,109,126 Hailes Oct. 29, 1963 

1. IN AN ELECTROMAGNETIC RELAY, A CORE STRUCTURE AND AN ARMATURE PIVOTALLY MOUNTED TO HAVE ITS OPPOSITE ENDS COOPERATE WITH SAID CORE STRUCTURE, SAID CORE STRUCTURE PROVIDING DISTINCT MAGNETIC FLUX PATHS FOR EACH OF THE TWO POSITIONS OF SAID ARMATURE, A WINDING ON SAID CORE STRUCTURE ENERGIZABLE SELECTIVELY TO PRODUCE FLUX OF EACH OF TWO POLARITIES IN SAID CORE STRUCTURE, AND A PERMANENT MAGNET MOUNTED IN SHUNTING RELATIONSHIP WITH A PORTION OF SAID CORE STRUCTURE AND CAUSING THE SATURATION OF THAT PORTION OF SAID CORE STRUCTURE TO CAUSE SAID FLUX FROM SAID WINDING TO PASS SELECTIVELY THROUGH SAID DISTINCT FLUX PATHS TO SAID ARMATURE DEPENDENT UPON THE POLARITY OF SUCH FLUX. 